Oestrone is one of three types of oestrogen made by the body. The other types of oestrogen are called oestradiol and oestriol. Oestrone is primarily produced by the ovaries as well as by adipose tissue and the adrenal glands. It has a much weaker biological activity than oestradiol. Oestrone is the major type of oestrogen hormone produced in any quantities in postmenopausal women.
Very little is known about how the production of oestrone is controlled. In premenopausal women, about 50% of oestrone is produced by the ovaries. The remaining 50% is produced by fat tissue and the adrenal glands, which are also the sources of oestrone in children, men and postmenopausal women. Because oestrone is less active than oestradiol, it is thought that oestrone may act as a reservoir that can be converted into oestradiol as needed.
Increased oestrone production can occur in women with breast cancer and in men undergoing treatment for testicular or prostate cancer (which reduces testosterone production). Obese women also produce more oestrone from their fat tissues. Overproduction of oestrone may be associated with the development of breast and endometrial cancer in women. Aside from this oestrone production may affect health in both positive and negative ways, but the full extent of this is currently not known.
Low levels of oestrogens cause osteoporosis, fatigue, hot flushes, loss of libido and depression. As oestrone is the main oestrogen in postmenopausal women, it is thought that low levels may worsen these symptoms (which are also common during the menopause), particularly in the case of osteoporosis. However, further research is needed to confirm this.
Last reviewed: Mar 2018